Violence rates fluctuate from generation to generation. Of initial interest is whether these differences over time are due to differences between cohorts or differences in social and environmental factors. The primary question to be answered is "Why are some generations more violent than others?" It is my career goal to answer this question. My career goal is to become an independent researcher on the processes of violence trends by coupling my solid foundation of injury research and epidemiology with new skills in psychology, criminology and statistics. My aim is to further our knowledge about why violence rates change over time and bridge the gap between various disciplines to be able to assess this multi-factorial public health problem. Empirical explanations are still longing on the major public health problem of why the level of violence fluctuates over time. Major limitations of these studies include the exclusion of confounders, not utilizing true longitudinal data, and the presence of both the ecologic and individualistic fallacies. Currently violence trends are not clearly understood and a diversity of contrasting explanations exists, including increased prevalence in certain age cohorts (cohort effect) and social risk factors occurring during certain periods of time (period effect). A major reason that so many explanations exist is that the causes for violence trends are multifactorial and occur at different levels - e.g., the community and the individual. The study of these various factors and levels are rooted rather independently in various public health, sociologic, and medical disciplines. The training program I propose will provide me with additional skills in (1) developmental psychology, (2) criminology and (3) advanced statistics through classes, seminars, and one-on-one training with my career development committee. We have conducted initial analysis of the PYS through our first generation model and have found that cohort effects are rendered insignificant by period effects, suggesting the importance of social factors on violence trends. My research program proposes a series of analyses culminating in the development of a second-generation model - our proposed contextual-developmental model for violence. This model will expand on the known individual developmental pathways developed by Rolf Loeber my mentor for this proposal, by the inclusion of social and environmental factors. Knowledge from these aims and from future work stemming from this proposal can be used to help integrate public health and criminal justice prevention programs into an overall program that will be more effective than many efforts in the past (49). Primary, secondary, and tertiary strategies aimed at the human, environmental, and instrumental elements of violence will ultimately be possible.